The quote really depends on where you live as labour costs differ across the world. Next question is how labour intense is the fix and whether it makes sense to invest that much time and money into the instrument. Say, it will take a luthier 3 hours to work on the instrument and the rate is $100/hr. Based on a quick search, Walden does not seem to be an expensive brand. If you can buy a comparable used instrument for $300 or so, IMO it may make more sense to replace the instrument instead of fixing. Unless, you have some special reasons to keep this specific instrument.
The other question is how bad is the crack. I would recommend taking your instrument to a couple local luthiers to get independent opinions, then check the market form used instruments, and then make a decision.
One more important question is why this happened in the first place. Unless it has been improperly stored or handled, this kind of damage shouldn't normally occur on itself and to me this raises a serious question about the quality of the instrument. If the crack appeared "on itself" with no apparent reasons, this can happen again and you may end up pouring lots of money into fixing it instead of, say, upgrading to a better quality instrument.
Update: I just noticed that this question was posted 10 months ago. Probably, this is not so relevant for you anymore, but of you fixed your guitar, keen to know about it :)